package com.dreamchaser.familydevice.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadPoolExecutor;

/***
 *
 *
 * @Author: SJie
 * Date: 2020/2/20 下午1:59
 * Description: 注解形式开启线程池调用
 *
 */
@Configuration
@EnableAsync
public class ThreadPoolTaskConfig {
    /**
     *   默认情况下，在创建了线程池后，线程池中的线程数为0，当有任务来之后，就会创建一个线程去执行任务，
     *    当线程池中的线程数目达到corePoolSize后，就会把到达的任务放到缓存队列当中；
     *  当队列满了，就继续创建线程，当线程数量大于等于maxPoolSize后，开始使用拒绝策略拒绝
     */

    /** 核心线程数（默认线程数） */
    private static final int corePoolSize = 20;
    /** 最大线程数 */
    private static final int maxPoolSize = 50;
    /** 允许线程空闲时间（单位：默认为秒） */
    private static final int keepAliveTime = 10;
    /** 缓冲队列大小 */
    private static final int queueCapacity = 50;
    /** 线程池名前缀 */
    private static final String threadNamePrefix = "Async-Service-";

    @Bean("taskExecutor") // bean的名称，默认为首字母小写的方法名 @Async("taskExecutor")
    public ThreadPoolTaskExecutor taskExecutor(){
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(corePoolSize);
        executor.setMaxPoolSize(maxPoolSize);
        executor.setQueueCapacity(queueCapacity);
        executor.setKeepAliveSeconds(keepAliveTime);
        executor.setThreadNamePrefix(threadNamePrefix);

        // 线程池对拒绝任务的处理策略
        // CallerRunsPolicy：由调用线程（提交任务的线程）处理该任务
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        // 初始化
        executor.initialize();
        return executor;
    }

    @Bean("singletaskExecutor")
    public ExecutorService threadPoolSingle(){
        ExecutorService executorService = Executors.newSingleThreadExecutor();
        return executorService;
    }

    /**
     * 固定线程数量的线程池
     * @return
     */
    @Bean("executorService")
    public ExecutorService threadPoolFix(){
        int nofProcessors = 2*Runtime.getRuntime().availableProcessors();
        ExecutorService executorService = Executors.newFixedThreadPool(nofProcessors);
        return executorService;
    }
}
